Dynamic characteristics of a domestic freezer with a microchannel flat-tube condenser

Abstract

In this study, a microchannel flat-tube condenser was introduced to a domestic freezer, and experiments were conducted to investigate the dynamic characteristics of the system at different ambient temperatures. Based on the dynamic variations of temperature in the main components, the refrigerant migration during the compressor-off stage and cooling output performance during the compressor-on stage were analyzed. The results show that the time proportion of the no-cooling output stage increased from 4.9% to 7.3%, while that of the refrigerant migration decreased from 25.6% to 21.2%, and energy consumption for no-cooling output stage increases from 0.0016 kW·h to 0.0023 kW·h as the ambient temperature increased from 16 °C to 32 °C. In addition, the freezer was compared to a system with a traditional circular tube condenser. The results show that the microchannel heat exchangers could contain more refrigerant charge due to the multi-channel structure during the compressor-off stage, weakening the “evaporative cooling” effect and reducing the migration loss. Therefore, the microchannel flat-tube condenser exhibited better stability at different ambient temperatures. The results of this study elucidate dynamic characteristics and advantages of applying a microchannel flat-tube condenser to a freezer, and provide a direction for reducing the energy consumption of a domestic freezer.